rb_str_buf_new always allocates at least 127 bytes of capacity, even
when less is requested.
> ObjectSpace.dump(%w[a b c].join)
{"address":"0x7f935f06ebf0", "type":"STRING", "class":"0x7f935d8b7bb0", "bytesize":3, "capacity":127, "value":"abc", "encoding":"UTF-8", "memsize":168, "flags":{"wb_protected":true}}
Instead, by using rb_str_new and then setting the length to 0, we can
allocate the exact amount of memory needed, without extra capacity.
> ObjectSpace.dump(%w[a b c].join)
{"address":"0x7f903fcab530", "type":"STRING", "class":"0x7f903f8b7988", "embedded":true, "bytesize":3, "value":"abc", "encoding":"UTF-8", "memsize":40, "flags":{"wb_protected":true}}
Single assignment with rescue modifier applies rescue to the RHS:
a = raise rescue 1 # a = (raise rescue 1)
Previously, multiple assignment with rescue modifier applied rescue
to the entire expression:
a, b = raise rescue [1, 2] # (a, b = raise) rescue [1, 2]
This makes multiple assignment with rescue modifier consistent with
single assignment with rescue modifier, applying rescue to the RHS:
a, b = raise rescue [1, 2] # a, b = (raise rescue [1, 2])
Implements [Feature #8239]
Fixes [Bug #8279]
This reverts commit c9eb8f82e9.
The change caused "implicit declaration" warning and actual segfault.
```
/tmp/ruby/v2/src/trunk-gc-asserts/enc/gb2312.c: In function ‘Init_gb2312’:
/tmp/ruby/v2/src/trunk-gc-asserts/enc/gb2312.c:6:31: warning: implicit declaration of function ‘rb_enc_find’ [-Wimplicit-function-declaration]
rb_enc_register("GB2312", rb_enc_find("EUC-KR"));
^~~~~~~~~~~
/tmp/ruby/v2/src/trunk-gc-asserts/enc/gb2312.c:6:31: warning: passing argument 2 of ‘rb_enc_register’ makes pointer from integer without a cast [-Wint-conversion]
<command-line>:0:19: note: expected ‘OnigEncoding {aka const struct OnigEncodingTypeST *}’ but argument is of type ‘int’
/tmp/ruby/v2/src/trunk-gc-asserts/regenc.h:231:12: note: in expansion of macro ‘ONIG_ENC_REGISTER’
extern int ONIG_ENC_REGISTER(const char *, OnigEncoding);
^~~~~~~~~~~~~~~~~
```